From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423165AbcFHI42 (ORCPT ); Wed, 8 Jun 2016 04:56:28 -0400 Received: from terminus.zytor.com ([198.137.202.10]:54796 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751666AbcFHI40 (ORCPT ); Wed, 8 Jun 2016 04:56:26 -0400 Subject: Re: [PATCH 02/10] x86, asm: use bool for bitops and other assembly outputs To: Ingo Molnar , Peter Zijlstra References: <1465342269-492350-1-git-send-email-hpa@linux.intel.com> <1465342269-492350-3-git-send-email-hpa@linux.intel.com> <20160608074956.GO30154@twins.programming.kicks-ass.net> <20160608082835.GB9645@gmail.com> <20160608083340.GC9645@gmail.com> Cc: "H. Peter Anvin" , Thomas Gleixner , Linux Kernel Mailing List , Andy Lutomirski , Borislav Petkov From: "H. Peter Anvin" Message-ID: <02ee64ce-257a-ba93-1f49-6877f5e4f6db@zytor.com> Date: Wed, 8 Jun 2016 01:55:19 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0 MIME-Version: 1.0 In-Reply-To: <20160608083340.GC9645@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/08/16 01:33, Ingo Molnar wrote: > > Note that this particular build error was introduced by b0bdba9825fe, a later > patch in this series - but in generaly I'm uneasy about allowing function > signatures diverge between architectures. > For the bitops, they already do: PowerPC, for example, have "unsigned long" in places where x86 has "int". This is obviously undesirable, but apparently we have not found it enough of a problem to deal with. One could easily argue the ppc definition is the better one; I was myself considering promoting the x86 side to "long" to handle enormous bitmaps. At the same time, it is hard to avoid the fact that ppc has unsigned bitops operations and x86 has signed ones when they are both native instructions. -hpa